Automatic throttle control



E. A. WINFIELD AUTOMATIC-THROTTLE CONTROL Dec. 7, 1937.

Filed June 15, 1936 .2 Sheets-Sheet l Inverzfqr. ,Edwardjl Ulla/Lela,

Dec. 7, 1937; E. A. WIN FIE LD I AUTOMATIC THROTTLE CONTROL Filed June1.5, 1936 2 Sheets-Sheet 2 r w 6 M4 W ,9. wa l 4244 Patented Dec. 7,1937 2,101,605 3 AUTOMATIC rnnorrtn common.

NT OFFICE Edward A. Winfield, La Canada, Calif assignor to CaliforniaMachinery & Supply 00., Ltdl, Los Angeles, Calif., a corporation ofDelaware Application .lune 13, 1936, Serial No. 85,092

13 Claims.

This invention relates generally to fuel feeding apparatus for internalcombustion engines, and has for its main purpose to provide an automaticthrottle control acting in accordance 5 with pressure conditions in theengine air supply passage beyond the throttle in the direction of airflow, to economize on fuel by causing the throttle to cut off the normalidling fuel supply under certain conditions of engine operation, as

W when the manifold pressure decreases below idling manifold pressure,or, where the invention is applied to an automobile engine, whenthevehicle is driving the engine in down hill operation.

In its preferred form, the invention embodies a suitable pressureresponsive member actuated in accordance with pressure variations in theair suction passage at the outlet side of the throttle, and operativelyconnected to the throttle in a manner such that under certain condi- 20tions of operation the pressure responsive member will move the throttlein an opening direction. When the engine is operating at substantiallyidling speed and for some reason tends to stall, causing the suctionpassage outlet pressure to increase somewhat from normal idlingpressure, the throttle control acts automatically to increase thethrottle opening momentarily or until the idling manifold pressure isrestored'to 20 normal. The principal novel feature of the inventionhowever is the automatic cut-off for discontinuing the normalidling fuelsupply under operating conditions when it is desirable to avoid usingunnecessary'fuel. For reasons that. will 35 later appear, the throttlecontrol may advantageously, though net necessarily, be connected with achoke valve in carbureter installations, so that the operation of thethrottle control is modified in accordance with movements of the 4 chokevalve.

The invention has a number ofgadditional aspects and objects, but allthese as wellas'the fea- Fig. 3 is a fragmentary section on line 3-3 ofi 1;

Fig. 4 is a sectional view of the carbureter proper; and A 'Fig. 5 is aview similar to Fig. 2 illustrating a b variational form of theinvention.

It is to be understood that the invention is generally applicable tovarious different types of engine fuel feeding apparatus 'utilizing athrottle controlled suction passage through which air is taken to theengine. The present automatic throttle control is convenientlyapplicable to the ordinary gasoline carbureter, and for the purpose ofillustrating and describing a typical and specific embodiment of theinvenlb tion, I have shown the throttle control to be applied to acarbureter which in itself comprises the subject matter of my copendingapplication, Ser. No. 85,093, entitled carbureter and filed on even dateherewith. For purposes of the present application, a brief generaldescription of the carbureter will sumce, since the invention is in noway concerned with the carbureter details, and the latter may be morefully ascertained by reference to the copending application referred to.

In the sectional view of Fig. 4, the carbureter is shown to comprise asuction passage Ml having an air inlet ii and a fuel and air mixtureoutlet I2, the flanged end i211 of which is bolted to the engine intakemanifold it. As used herein, and except when otherwise limited, the term"suction passage may be regarded as inclusive of the engine manifold l3.The flow of air to the engine is controlled by a suitable throttle,typically the usual butterfly valve l4, carried on shaft l5 and operatedby a lever arm IS, the throttle opening against a suitable springresistv ance conventionally illustrated by spring ll attached to leverl6. Choke valve l8 positioned within the inlet II is mounted on a shaftl9 offset from the axial center of the carbureter suction passage and.operated in the usual manner by 'a lever 20 attached to its outer end.Fuel is fed from inlet line 2| into the supply chamber 22 under controlof a float operated valve 23, and from, the supply chamber the fuelflows to main fuel nozzle generally indicated at 24 and into thedisplacement chamber 25 of a positive displacement accelerating fuelfeeding means indicated at 26.

Fuel is fed from the main fuel nozzle 24 into a metering tube 21 withina passage 28 through of the passage at the inlet. During periods ofacceleration, fuel also is discharged into the metering tube frompassage 30 leading from the displacement chamber 25 of the acceleratingfuel supply means 26. The fuel and air mixture formed within thediversion passage is discharged from the outlet end 21a of the meteringtube into the throat of the venturi 3| in the main suction passage, andis thence taken into the intake manifold under control of throttle l4.During engine idling operation, fuel is supplied to the suction by wayof an idling by-pass passage 32 receiving its fuel via passage 33 fromthe bore containing the main nozzle 24, the fuel being discharged frompassage 32 through orifice 34 whose effective size is regulated byneedle valve 35. In its normal idling position, throttle I4 is to theoutlet suction being cut off from the de- I livery orifice.

The automatic throttle control, with which the invention is moreparticularly concerned is generally indicated at 36 in Fig. l, and inits preferred form is shown to comprise a body 31 suitably mounted onthe carbureter body, as by attachment to boss 38. The body 31 contains acylindric chamber 39 closed at its outer end by cover 40 carrying a stopscrew 4|. Chamber 39 contains a pressure responsive member in the formof a piston 42 having a rod 43 projecting through the inner closed end44 of the body and attached by a pin and slot connection at 45 with alever arm 46 rotatably carried on the throttle shaft l5.

Chamber 39 is vented to the atmosphere at opposite sides of the piston42 through orifices 41. and 48. The piston travel toward the right andin a throttle closing direction is' yieldably resisted by a coil spring49 confined between the piston and end wall 44 of the body. is willlater appear under certain operating conditions the spring resistance isovercome by depression communicated to chamber 39 at the right of thepiston, causing the latter to travel to the point of engagement withsleeve 59. Then, as the depression in the chamber is further increased,additional piston travel in throttle closing direction is permitted bycompression of spring 5| confined lggtween wall 44 and'the flanged endof sleeve tially compressed condition by adjustment of nut 52 so thatthe spring maintains a predetermined and somewhat greater resistance tothe piston travel, than the resistance imposed by spring 49.

When the depression in chamber 39 is relieved, spring 49 moves piston 42toward the left to a limiting position of engagement with stop screw 4|,during which time the throttle moves an angular distance of around 5from closed position to the dotted position |4b. It will be understoodthat piston 42 may have any suitable length of travel to give thethrottle the desired range of movement under the influence of thepiston, although a range of throttle movement of around 5 will generallygive satisfactory performance.

A lug 54 integral with the lever arm 46 that ro- Spring 5| normally ismaintained in a par-.

56 on the throttle shaft to limit the throttle position in a closingdirection and to open the throttle as piston 42 travels toward the left.When the throttle is manually rotated to full open position, projection56 swings in the direction of the arrow and away from stop 55 intoengagement with a downwardly facing shoulder 51 on the carbureter body.It will be noted that by reason of its connection with the piston 42,stop 55 will be variably positioned relative to the throttle projection55 depending upon the position of the piston, which in turn is dependentupon the pressure conditions existing within chamber 39.

The suction passage pressure at the outlet or manifold side of thethrottle is communicated to chamber 39 by way of passage 58, see Fig. 3,

leading at 59 from a suitable location beyond the throttle andconnecting at 60 with a bore 6| communicable with the piston chamberthrough passages 62 and 63. Bore 6| contains a valve 64 normally held inthe raised position of Fig." 1 by a coil spring 65, and adapted to bemoved downward to close one or both of passages 62 and 63 when engagedby cam arm 66 carried on the end of the choke valve shaft l9, as willlater appear.

In considering the operation of the throttle control device, letit-first be assumed that the engine is idling with the throttle insubstantially the position shown in Fig. 4, or perhaps slightly openedfrom that position. The depression existing at the outlet side of thethrottle and communicated to the'piston chamber 39 via passage 58, boreBI and passages 62 and 63, causes the piston 42 to assume the positionshown in Fig. 1, in which spring 43 is compressed and the piston is atsubstantially the point of engagement with the end of sleeve 50. If nowfor any reason the engine tends to stall or miss fire, there occurs areduction in the engine speed and a corresponding increase in thepressure within the suction passage at the engine side of the throttle.Im-

mediately as the pressure increases within the suction passage outleti2, the pressure increase is communicated via passage 58 to the pistonchamber 39 causing spring 49 to move the piston toward the left and tomove the throttle in an opening direction to admit more fuel and air tothe manifold momentarily or until manifold pressure is restored tonormal.

The throttle control automatically responds to the pressure increase inthe suction passage underthe conditions described, and automaticallyopens the throttle just the necessary distance for preventing thestalling of the engine. That distance may of course vary in differentinstallations, depending upon the type of engine and its fuelrequirements, and the operation of the fuel supply apparatus. After theengine again is running smoothly and the normal depression is restoredin the'suction passage outlet, piston 42 again moves to the right,returning the throttle to its normal idling position. It will beunderstood that in its throttle opening movement, the control device 36overcomes the resistance of the usual throttle closing spring i'l. Asthe operator opens the throttle beyond idling position to increase theengine speed, the suction passage outlet pressure i'ncreases, causingspringv 49 to move piston 42 into engagement with the stop 4|, asillustrated in Fig. 2.

Under certain conditions of operation, as for example when the vehicleis running down grade and is driving the engine, it may be desirable toentirely or substantially entirely cut oil the supply of fuel to theengine. Assuming the throttle to be in substantially the position ofFig. 4 and the vehicle to be driving the engine, an abnormally highdepression, in excess of the normal idling depression, is created withinthe suction passage outlet i2. This high depression, communicated tochamber 39, moves the piston to-v ward the right against the resistanceof both springs t9 and 5!, and-swings stop 55 a distance sufficient topermit throttle M to close fully to the dotted line position Ma. In thisposition the throttle edge completely closes orifice 3t at the suctionpassage outlet side and cuts off the norrnal idling fuel deliverythrough passage 32, thus eifeoting a saving of the fuel that otherwisewould be wasted during periods when the engine is being driven. Instating that the throttle edge closes the orifice, I mean that theorifice is substantially entirely out off from the manifold suc-.

. deviceiili inoperative to insure that the throttle will remain in aclosed position set by adjustment of the throttle control arm 16. Forthis purpose I provide a valve 64 which when, engaged by cam arm 66 asthe choke valve is closed, is moved downwardly toa position in which itcovers both ports 62a and 63a, see Fig; 2 to render the pistonunresponsive to pressure conditions beyond the throttle by cutting offcommunication between passage 58 and chamber 39. It may however bedesirable in starting when the choke valve is used, to take advantage ofthe throttle.

control device 36 for the purpose of causing the throttle to beautomatically opened in the manner previously described, to prevent theengine from stalling in the event the fuel mixture becomes too rich.Under this condition, the choke may be closed to the extent of causingvalve 64 to close only port 62a, leaving port 6311 open to maintain acommunication of suction from passage 58 to the piston chamber viapassage 63. When the engine is idling then, piston 42 will have beenmoved to the right just to the point of covering 'passage 63. Should thesuction passage outlet pressure increasedue to the tendency of theengine to stall, piston 42 is permitted to move toward the left, awayfrom passage 63, during which interval of travel the throttle will havebeen opened sufiiciently'to keep theengine running.

Fig. 5 shows a variational type of throttle control device generallysimilar to the previouslydescribed form, although somewhat simplified inthat it omits the feature of providing a second spring adapted to becompressed by the piston -during final closing movement of the throttlewhen the engine is being driven, and lacking the feature of a chokevalve that may permit only partial piston travel under control of thechok. Here the piston travelin a throttle opening direction is opposedby a single coil spring 10 and the piston travel is limited byengagement .with a stop it at a point corresponding to the illustratedthrottle position in which the idling fuel orifice 34 remains open atfully closed throttle position. When the choke valve is closed, arm 66depresses rod I2, unseating valve 13 to bleed including a suctionpassage containing a throttle and having an air inlet and an outlet;means for supplying fuel to said passage through an orifice that isclosed by said throttle when the throttle is fully closed, but which isopened by the throttle as the latter is slightly opened, means tendingnormally to maintain said throttle in partially open positionduring-idling engine operation, and means for moving said throttle tofully closed position in which the throttle closes said orifice, whenthe engine is being driven by the vehicle.

2.'In engine fuel feeding apparatus including a suction passagecontaining a throttle and having an air inlet and an outlet; means forsupplying fuei to said-passage through an orifice that is closed by saidthrottle when the throttle is fully closed, but which is opened by thethrottle as the latter is slightly opened means tending normally tomaintain said throttle in partially open position during idling engineoperation, and,

pressure responsive means communicating with said suction passage at theoutlet side of the throttle and operating to move said throttle to fullyclosed position in which the throttle closes said orifice, when thepressure in said suction passage at the outlet side of the throttle decreases belowthe pressure existing therein during idling operation.

3. In enginefuel feeding apparatus including a suction passagecontaining a throttle and having an air inlet and an outlet; means forsupplying fuel to said passage through an orifice that is closed by theedge of said throttle when the throttle is fully closed, but which isuncovered by the throttle as the latter is slightly opened, and pressureresponsive throttle control means including a throttle stop movable withrelation to the throttle, said pressure responsive means communicatingwith said suction passage at the outlet side of the throttle and tendingnormally to maintain the stop in such position that the throttle is inpartially open position when the engine is idling, and operating toactuate the stop so that said throttle moves to fully closed position inwhich the throttle closes said orifice when the pressure in said suctionpassage at the outlet side of the throttle decreases below the pressureexisting therein during idling operation.

4. In an engine carbureter having a body containing a suction passagehaving an air inlet and an outlet, and a throttle within said passage;the combination comprising, means for supplying fuel to said passagethrough an orifice that is closed by said throttle when the throttle isfully closed, but which is uncovered by the throttle as the latter isslightly opened, means tending normally to maintain said throttle inpartially open position during idling operation, a body mounted on thecarbureter body and con taining a chamber communicating through apressure in said suction passage at the outlet throttle, whereby apredetermined reduction in said pressure will move the throttle toward aclosed position, but when said pressure increases beyond that reducedpressure, said member will move the throttle in an opening direction,and valve 'means for relieving suction in said chamber at said side ofthe pressure responsive member to affect the responsiveness of saidmember to said suction passage pressure changes.

6. In engine fuel feeding apparatus including a suction passagecontaining a throttle and having an air inlet and an outlet; thecombination comprising, a body having a chamber therein, a pressureresponsive member within said chamber, means connecting said member withthe throttle, means communicating to the chamber within said body at oneside of said member the suction passage pressure at the outlet side ofthe throttle, whereby a predetermined reduction in said pressure willmove the throttle toward a closed position, but when said pressureincreases beyond that reduced pressure, said member will move thethrottle in an opening direction, a choke valve in said suction passage,and valve means operable with closing movement of said choke valve torelieve suction in said chamber to affect the responsiveness of saidmember to said suction passage pressure changes.

r- 7. In engine fuel feeding apparatus including a' suction passagecontaining a throttle and having an air inlet and an outlet; means forsupplying fuel to said passage through an orifice that is closed by theedge of said throttle when the throttle is fully closed, but which isuncovered by the throttle as the latter is slightly opened, pressureresponsive means tending normally to maintain said throttle in partiallyopen position, means communicating to said pressure respon sive meansthe suction passage pressure at the outlet side of the throttlefwherebysaid pressure under normal engine idling operation will move thethrottle toward closed position but not sufficiently to close saidorifice, said pressure responsive means however being responsive tofurther decrease in said suction passage pressure,

to move said throttle to fully closed position in which the throttlecloses said orifice.

8. In engine fuelfeeding apparatus including a suction passagecontaining a throttle and having an air inlet and an outlet; means forsupplying fuel to said passage through an orifice that is closed by theedge of said throttle when, the throttle is fully closed, but which isuncovered by the throttle as the latter is slightly opened, pressureresponsive means tending normally to maintain said throttle in partiallyopen position, means communicating to said pressure responsive means thesuction passage pressure at the outlet side of the throttle, wherebysaid pressure under normal engine idling operation will move thethrottle toward closed position but not sufficiently to close saidorifice, yielding means imposing a predetermined resistance to furtherclosing movement of the throttle, said pressure responsive means beingresponsive to a. pressure decrease in said suction passage pressurebelow normal idling pressure, to move said throttle to fully closedposition in which the throttle closes, said orifice.

9. In engine fuel feeding apparatus including a suction passagecontaining a choke valve, a. throttle and having an air inlet and anoutlet; the combination comprising, pressure responsive means tending tomaintain said throttle in partially open position, means communicatingto said pressure responsive means the suction-passage pressure at theoutlet side of the throttle, whereby a predetermined reduction in saidpressure will move the throttle toward closed position, but when saidpressure increases beyond that reduced pressure, said pressureresponsive means will move the throttle in an opening direction, and.means operating with closing movement of said choke valve to render saidpressure responsive means substantially uninfluenced, by said suctionpassage pressure changes.

10. In engine fuel feeding apparatus including a suction passagecontaining a choke valve and a throttle, said passage having an airinlet and an outlet; the combination comprising, pressure responsivemeans tending to maintain said throttle in partially open position,means communicating to said pressure responsive means the suctionpassage pressure at the outlet side of the throttle, whereby apredetermined reduction in said pressure will move the throttle towardclosed position, but when said pressure increases beyond that reducedpressure, said pressure responsive means will move the throttle in anopening direction, and means for modifying the action of said pressureresponsive means in accordance with the operation of said choke valve.

11. In engine fuel feeding apparatus including a suction passagecontaining a choke valve and a throttle, said passage having an airinlet.and an outlet; the combination comprising, pressure responsivemeans tending to maintain said throttle in partially open position,means communicating to said pressure responsive means the suctionpassage pressure at the outlet side of the-throttle, whereby apredetermined reduction in said pressure will move the throttle towardclosed position, but when said pressure increasesbeyond that reducedpressure, the throttle will move in an opening direction, and meansactuated in accordance with closing movement of said choke valve forcontrolling the communication of said suction passage pressure to thepressure responsive means.

12. In engine fuel feeding apparatus including a suction passage havingan, air inlet and an outlet, a throttle actuating shaft; the combinationcomprising, pressure responsive means tending to maintain said throttlein partially open position, means communicating to said, pressureresponsive means the suction passage pressure at the outlet side of thethrottle, whereby a predetermined reduction dn said pressure will movethe throttle toward closed position, but when said pressure increasesbeyond that reduced pressure, said pressure responsive means will movethe L throttle in an opening .direction, a throttle stop mounted on saidthrottle shaft for swinging movement relative thereto and actuated bysaid pressure responsive means, and means carried by memos it. In enginefuel feeding apparatus including a suction passage having an a r inletand an outlet, a throttle and a, throttle actuating shaft; thecombination comprising, a pressure responsive means including a springtending to maintain I side of the throttle, whereby a, predeterminedreduction in said pressure will compress said spring and move thethrottle toward closed position, but when said pressure increases beyondthat reduced pressure, said spring will move the throttle in an openingdirection, an arm pivotally mounted intermediate its ends on saidthrottle shaft, 2. throttle stop on said arm, means carried by saidthrottle shaft and adapted. to engage said stop to limit throttlemovement in a, closing direction, and means connecting said. am withsaid pressure responsive means.

EDWARD A. WINFIELD.

